Clock balance escapement device



Feb. 6, P, J MCCULLOUGH CLOCK BALANCE ESCAPEMENT DEVICE Filed Nov. 15,1947 2 Sheets-Sheet l v INVENTORI PAUL J. MCCULLOUGH AT TORNEY.

Feb. 6, 1951 P. J. M CULLOUGH CLOCK BALANCE ESCAPEMENT DEVICE 2Sheets-Sheet 2 Filed Nov. 15, 1947 FIG. 9.

INVENTORi PAUL J. MCCU LLOUGH ATTORNEY,

Patented Feb. 6, 1.951

UNITED PATENT OFFICE 'JGLOCKZ BALANCE ESCAPEMENT :DEVICE .Paul..J.'1Mc"Cullough, St. Louis, M0,, assignor,;by

mesne assignments, ,to'iThe' Toastswell Commanmllneorporatd, St."LouisfiMo; a corpora- -tion--of Missouri v-ApplicationNovember 15,.1947, Serial No..'7-86,1'89

Claims. r1 Theinvention relates to clock, mechanismland moreparticularlyto clock mechanism; for wuselin timing electric toasters.and other .devices.

Reference -is made .to PatentiNoQ862,836,-is-

sued to the present. applicantNovember 1(1, 194.4,

noiseless, if special attentionis .directedto it, a

slight clicking sound can be, heard.

The main object of the present .invention'is to eifect even more quietoperationthan heretofore of clock mechanisms constructed -of parts .madeand assembled in quantities andof inexpensive-materials, such asmetalstampings, and to keep the parts in adjustmentirrespective of Wear.

This is accomplished "by .causing the spring member to thrust thebalance wheel 'shaft'substantially in the direction of thrust exertedbythe scape'wheel on the balance wheel. andpreferably towards the vapex of.an angular aperture. Thisarrangement' restrains movement of thelbalancewheel in "directions both parallel antiperpendicular to the direction ofthrust.

In Patent No. "2,362,835, the'balance iwheel comprises a pair of discsclamping between them the base of the Ll-shapedpallet and one of .whichpalletlegs. The balance wheeliiisc preferably is madeof sheet metalapproximately .050"1thick and thepallet preferablyis made of. springwire approximately .0l4" in'diameter. "It is impractical to punch acircular holein sheet metal smaller in diameter than the .thiekness ofthe metal, so that'the diameter eftheholespunched in the balance wheeldisc for the palletdegsis relatively larger .than the diameter ofthepallet legs. The metal of the discsurrounding'thepallet legs cannotreadily be pressed firmly into .surrounding engagement with the palletlegs. En-

is provided with circular openings to receivethe legs. .to closelyapproach the diameter of 'the,.pa1let legs andto permit the metal at'theside of the .slotsto be pressed firmly into engagement .with the palletlegs and securelyhold them in position held in spaced .relation'by posts)3. gears, .4, 5 and fi aremounted upon individual gagement anddisengagement of the pallet with :the scape wheel causes constantflexing of the pallet material where theilegsjointhe connecting partwhich has been strained initially in makingthe sharp bend and thismayresult'inithe "legsfracturing at the bend. Also, when press-.ingthemetal about the disc apertur into engagement with the pallet"legs, the latter are 'likelyto shift inthe apertureresultingin'inaccuraciesin the finished balance wheel.

.Another object is to overcome these structural .difficultiesbyprovidingelongated narrow slots in ,the balance Wheel disc to receivethepallet Theaslots can be made sufiiciently-narrow and also ,toreinforce them at the. bent portions. With this arrangement, only asingle disc is needed and the pallet legs maybemade sepa- ..rately.andof straight pieces of thin wire and Withoutlthe connecting parttherebetween.

"The above and other-detail objectsas willsappear below are attained bthe structureillustrated in the accompanying.drawings. in which:

.Figure l is a side view of a clock mechanism embodying the invention,one side plate being .removed.

"Figure 2 is a detail vertical sectiontaksnapproximat'elycn the line 22ofFigure'l.

L'Figures 3 and 4 are detail vertical sections, drawnto enlarged scale,taken on line :33.of Fjgure'2 and showing the scapewheel and the balancewheel and associated partsin different positions.

JFiigure'S'isa detail of a portion of the spring "member, the balancewheelv shaft in vertical sec- .tion andits bearing, drawn to enlargedscale.

Figure 6 is a perspective view of a balance wheel constructedaccordingto the invention.

"Figure "!.is a side view thereof.

Figure 8 is a detail side viewof a balance Wheel disc before the palletsand .shaftare assembled thereto, and

.Figure 9 View similar to Figurel3 show ing another form of theinvention.

The clock frame comprises .sideplates land! A vtrainpf shaftsjournaledin plates [and]: and associated with pinions 1,5;and L9,..respectively.Arshaft 5.0

.mounting pinion ii and journaled in circular .apertures mainplates I Iand.2 also. carries :a scape In the embodiment shown in Figures 1 to 8,associated with scape wheel I I is a balance wheel I2 mounted on a shaftI3 journaled in square apertures I 3a in plates I and 2. The apex of oneof the angles between adjacent sides of each aperture I3a preferably ispositioned at the end of aperture I3a remote from apertures Ida.

Balance wheel I2 comprises a single plate disc I4 having elongated slotsMd and provided with a pallet structure preferably formed by a U- shapedunit of small diameter spring wire with its cross piece I8 applied toone face of the disc and with its legs I6 and II extending outwardlyfrom the opposite face of the disc. After the pallet structure isapplied to the disc, the metal of the latter is deformed or offset totightly press the metal against opposite sides of the legs at pointsspaced from the apex of the sharp angle formed by the bends whichconnect elements I8 with elements I6 and II. With this arrangementfiexure of the pallet structure restricted to the portions of elementsI6 and II projecting from the disc and is not applied to the right anglebend in the wire where repeated flexing might readily result in failureor the wire.

Balance wheel I2 oscillates on its shaft to alternately engage anddisengage pallet legs i and II with the scape wheel teeth and the springquality of the pallet structure gives the balance wheel its oscillatorymovement and functions as does the hair spring in the usual clockmechanism. Furthermore, the yielding action of the pallet structureavoids the pronounced click usually present in inexpensive simple clockmechanisms and produces a quiet clock operation which is highlyadvantageous in timing devices for appliances such as toasters, etc.

To further contribute to the quiet efficient operation of this deviceand to avoid the necessity of fine fitting of the balance wheel shaftpintles IS in their bearings, a spring member 26 having a bow-likecontour with hooked ends extends around a post 3 and has one of its endsengaging a pintle I9 of shaft Ill and the other end engaging an inwardprojection 2I on plate I. Spring member 20 engages the adjacent surfaceof the associated pintle I9 and thrusts the opposite surfaces of bothpintles I9 toward the apices of the bearing surface angles of aperturesI 3a in a direction substantially in alignment with the generaldirection of thrust exerted by scape wheel II on balance wheel I2 as theteeth of scape wheel II alternately engage pallet legs IB and IT. Thisarrangement provides for rolling contact of pintle I9 of shaft I3 andthe associated looped end of spring member 2!! as do scribed in PatentNo. 2,362,836 mentioned above.

The force exerted on balance wheel I2 during its engagement by the scapewheel is in a direction substantially perpendicular to the palletengaging face of the tooth engaging the pallet leg. When a tooth ofscape wheel II engages pallet leg I6, as shown in Figure 3, thedirection of thrust of scape wheel II on balance wheel I2 is indicatedby arrow at. When a tooth of scape wheel II engages pallet leg II, asshown in Figure 4, the direction of thrust of scape wheel II on balancewheel I2 is indicated by arrow 1/. Between each such engagement, noforce is exerted by scape wheel iI on balance wheel I2 and shaft pintlesI9 may tend to move away from the opposing bearing surfaces of aperturesI3a, particularly when the pintle supporting bearing surfaces inclinedownwardly away from the apices. Spring member 2!! maintains shaftpintles IQ of balance wheel I2 in apertures I311. substantially in thepositions which they normally assume when balance wheel I2 engages scapeWheel II, thus quieting the mechanism. If the sides of apertures I3ashould become worn, the thrust of spring member 20 on balance wheelpintle I2 holds the balance wheel pintle against the bearing surfacesubstantially opposite to the scape wheel and thrusts the balance wheelin the direction of thrust of the scape wheel on the balance wheel.

The structure shown in Figure 9 is similar to that previously describedin Figures 1 to 8 except that spring member 30 has its looped endsengaging pintle 3| of scape wheel shaft 32 and pintle 33 of balanceWheel shaft 34. Apertures 32a and 34a both may be circular and receivepintles 3| and 33, respectively, but need not fit them closely. Springmember 30 engages adjacent surfaces of pintles SI and 33 and thrusts theshafts apart with the opposite surfaces of the pintles against thebearing surfaces of apertures 32a and 34a in a direction substantiallyin alignment with the general direction of thrust exerted by scape wheel35 on balance wheel 36 as the teeth of the scape wheel engage balancewheel pallet legs 3'! and 38.

The above described structures attain the objects set forth in theintroductory portion of this specification and provide rugged,inexpensive mechanisms which are so quiet as to be almost inaudible andwhich have long useful lives, notwithstanding rough handling and otherdisadvantageous conditions under which clocks must work when used in thetype of equipment mentioned.

The details of the structure may be varied substantially from thespecific disclosure herein without departing from the spirit of theinven tion and the exclusive use of those modifications coming withinthe spirit of the claims is contemplated.

What is claimed is:

1. In a clock escapement device, a balance wheel, a scape wheelassociated therewith, a shaft mounting said balance wheel, and anelement yieldingly thrusting said shaft in a direction substantially inalignment with the general direction of thrust exerted by said scapewheel on said balance wheel.

2. In a clock escapement device, a balance wheel, a scape wheel, shaftsmounting said balance wheel and said scape wheel and each hav ing ajournal, a plate having apertures receiving said journals and formingbearings therefor, said balance wheel and said scape wheel exertingthrusts one on the other in substantially opposite directions, and aspring element thrusting said balance wheel shaft in a directionsubstantially in alignment with the general direction of thrust exertedby said scape wheel on said balance wheel.

3. In a clock escapement device, a balance wheel, a scape wheelassociated therewith, shafts mounting said balance wheel and said scapewheel and each having a journal, said balance wheel having a pair ofwidely spaced pallets, said scape wheel alternately engaging saidpallets and thrusting said pallets in different directions, and a springthrusting said balance wheel shaft in a direction between the directionsof said thrusts.

4. In a clock escapement device, a balance wheel, a scape wheel, shaftsmounting said balance wheel and said scape wheel and each having ajournal, a plate having apertures receiving said journals and formingbearings therefor, and a spring element having one end anchored to saidplate and having the other end yieldingly thrusting said balance wheeljournal against the side of the associated aperture most remote fromsaid scape wheel.

5. In a clock escapement device, a balance wheel, ashaft mounting saidbalance wheel and having a journal, a plate having an aperture receivingsaid journal and forming a bearing therefor, said aperture having atleast two sides forming the apex of an angle, and a spring elementyieldingly thrusting said journal towards the apex of said angle.

6. In a clock escapement device, a balance wheel, a scape wheelassociated therewith, shafts mounting said balance wheel and said scapewheel, and a spring element thrusting said shafts in oppositedirections.

'7. In a clock escapement device, a balance wheel, a scape wheel, shaftsmounting said. balance wheel and said scape wheel and each having ajournal, a plate having apertures loosely receiving said journals andforming bearings therefor, and a spring element yieldingly thrustingsaid journals apart and against a side of the associated aperture.

8. In a clock escapement device, a balance wheel, a scape wheel, shaftsmounting said balance wheel and said scape wheel and each having ajournal, a plate having apertures loosely receiving said journals andforming bearings therefor, said balance wheel and said scape wheelexerting thrusts one on the other in substantially opposite directions,and a spring element thrusting said shafts in directions substantiallyin alignment with the general directions of thrust exerted by said scapewheel and said balance wheel on one another.

9. In a clock escapement device, a balance wheel, a scape wheel, shaftsmounting said balance wheel and said scape wheel and each having ajournal, a plate having apertures receiving said journals and formingbearings therefor, and an element engaging adjacent surfaces of saidjournals and yieldingly thrusting said journals apart and thrusting theopposite surfaces of said journals against boundaries of the apertures.

10. Structure as described in claim 9 in which the journal engagingelement comprises a spring having a hook at each end.

11. In a clock escapement device, a balance wheel, a scape wheelassociated therewith, shafts mounting said balance wheel and said scapewheel and each having a pintle, a plate having apertures receiving saidpintles, a spring element in engagement with said pintles and yieldinglythrusting said pintles apart against boundaries of the associatedapertures.

12. In a clock escapement device, a balance wheel, a scape wheelassociated therewith, shafts mounting said balance wheel and said scapewheel and each having a journal, a plate having apertures looselyreceiving said journals and forming bearings therefor, said balancewheel having a pair of widely spaced pallets, said scape wheelalternately engaging said pallets and thrusting said pallets indifferent directions, the reactions from said thrusts urging said scapewheel in directions substantially opposite to the directions of saidthrusts, and a spring thrusting said balance wheel shaft in a directionbetween the directions of said thrusts on said pallets and thrustingsaid scape wheel shaft in a direction between the directions of saidthrusts on said scape wheel.

13. In a clock escapement device, a balance wheel comprising a disc-likemember having a pair of slots, pallet structure consisting of a U ofspring wire with its cross bar adjacent one surface of said disc andwith its legs extending through said slots in said. member andprojecting from the other surface, portions of said member adjacent saidlegs tightly pressing against opposite sides of said legs outwardly oftheir connection to said cross bar.

14. In a clock escapement device, a balance wheel comprising a disc-likemember having an elongated slot, a flexible pallet extending throughsaid slot and held firmly therein by opposing portions of the discengaging opposite faces of said pallet substantially at the point wherethe pallet emerges from said disc.

15. In a clock escapement device, a mounting plate having asubstantially polygonal aperture, a balance wheel having a shaftprovided with a journal loosely received in said aperture, and a springelement exerting a constant thrust on said journal parallel to saidplate to hold the journal against play in a bearing formed by theconverging sides of an angle of said aperture.

PAUL J. MCCULLOUGH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

